Huh?

Huh, indeed. I misremembered how Hindi handles the 2nd person: there are three grades of respect: intimate 2PS (tuu hai), familiar 2PS/2PP (tum ho), and respectful 2PS/2PP (aap hain). I tried to map these to quasi-archaic English. Looking at verbal conjugation in an online grammar, I'd also forgotten that the 3rd person, singular and plural, is divided into 3rd person near and far from the speaker: yah hai / ye hain and vah hai / ve hain.

Ceci n'est pas un seing.